Improvement in pulp-screens for paper machinery



S. L. GOULD. Pulp-Screen for Paper-Makohinery No. 210.521.

Patented Dec. '3, 1878 WaZer 511. y.

N. PEI'ERS, FHOTD-LITHOGRAPHER, WASHINGTON, D. C.

"UNITED STATES PATENT OFFICE.

SIMEON L. GOULD, OF GARDINER, MAINE.

IMPROVEMENT IN PULP-SCREENS FOR PAPER MACHlN ERY.

Specification forming part of Letters Patent No. 210,521, dated December3, 1878; application filed November 4, 1878.

To all whom it may concern:

- Be it known that I, SIMEON L. GOULD, of Gardiner, Kennebec county,Maine, have invented certain new and useful Improvements inPulp-Screensfor Paper Machinery, of which the following is a specification:

My invention relates to that part of papermaking machinery known as thejoggingscreen'that is to say, the screen or strainer employed to arrestthe knots, lumps, or other foreign substances contained in the pulp, andto which an up-and-down or jogging motion is imparted by suitable means,to facilitate the passage of the pulp through the interstices of thescreen-the foreign matter being removed from the upper surface of thelatter at intervals of time, as occasion requires.

My invention consists, first, in the employment,-in connection with ajogging-screenof paper machinery, of jets or sprays of water, projectedfrom below upon the under side of the screen-plate, and so that thewater, under pressure from a suitable head, shall force its way'upwardthrough the slits or interstices of the said screen-plate, and, keepingsuch interstices free from obstruction, permit of free and rapid passageof the pulp through them,

and prevent formation and accumulation of strings, so called, about thelower edges of such interstices.

Andmy invention consists, secondly, in a screen composed of an uprightcylinder, wallowing in the pulp-vat, and containing at its upper part aforaminous shelf, which constitutes the screen-plate, this shelf beingplaced horizontal or oblique, as practice may determine to be best, andbeing pierced with slits,

I holes, or other attenuated perforations, through which the pulp isprecipitated, while the impurities remain upon its upper surface.

As is well known, pulp, for the manufac ture of paper, consists of anassemblage of fine fibers, of greater or less length, according to thecharacter of the paper to be made; and to enable these fibers to passthrough the interstices of the screen, it has been customary to piercethe screen-plate with attenuated slits rather than with small roundperforations.

Incidental details of my invention will be duly explained.

The drawings accompanying this specification, and illustrating myinvention, represent, in Figure 1, a vertical section, and in Figs. 2and 3 horizontal sections, of a device embracing my invention. 7

In these drawings, A represents an upright cylinder, supported androtated by a vertical axial shaft, B, such shaft being secured to thecylinder by any suitable means, but in the present instance beingsecured by a hub, O, to a horizontal shelf or plate, D, which spans theupper part of the cylinder A and constitutes the screen-plate, and whichis, in the present instance, pierced with a series of segmental,concentric, attenuated slits, a a, 850., through which the pulp admittedto the upper part of the cylinder passes. The shelf or screen-plate D,in lieu of being horizontal, may be placed sloping or oblique withrespect to the axis of the cylinder, should practice or circumstancesdemand; and the form, number, or size of the interstices a a may bevaried from the segmental slits above named, as I do not confine myselftoany arbitrary rule in this respect, so long as I provide a suitablescreening-surface. i For instance, the slits may be arranged in rows ofstraight, in lieu of segmental, lines, and may be placed parallel ortangential to the circumference of thecylinder.

The upper end of the shaft B is guidedby a bearing, 1), upheld bycross-bars c, &c., arranged above the cylinder A, and supported at theirouter ends upon posts (I, &c., erected upon corresponding bars 6, &c.,arranged below the cylinder, or upon the bottom of the chest E,whichcontains the screened pulp, and in 'whicht-he cylinder is immersedand wallows, the outlet-pipe by which the pulp escapes from the chest Ebeing so placed that a shallow space shall remain between the under sideof the screen-plate and the surface of. the pulp in such chest.

The lower end of the shaftB is stepped in any suitable manner to ahorizontal beam, F, placed at the bottom of the chest, the base of suchlever being pivoted, by a pivot, f, to a hanger of one of the bars 0, orto a post erected upon the bottom of the chest, or to one of theadjacent posts (I, as the case may be, while to the opposite or free endof the lever is swiveled the lower end of an upright rod,

9, whose upper end in turn passes loosely through a hole, 71, made in ahorizontal bar, 2', spanning two of the posts (I, and has a male screwout upon it, upon which a hand-wheel or nut, j, is screwed, and so as tobear upon the top of the bar The lower edge of the cylinder A iscorrugated or undulating, and below the cylinder and concentrictherewith, and supported firmly in position thereat, is an uprightcircular wall or ledge, Gr, whose upper edge is also corrugated orundulating. As the cylinder rotates, under the impulse of any primemover connected with its shaft, the two undulating sur faces in contacteffect an up-and-down or jogging motion of the cylinder and its screenwithin the chest E, which contains the pulp, with the result incident toscreens of this characterthat is to say, as the screen descends, thebody of air below it tends to blow or force the thin body of pulp uponthe screen-plate upward and out of the interstices, while, as the screenascends, the suction incident to the tendency to a vacuum below draws acertain portion of the pulp downward through the said interstices, or,in other words, screens such pulp.

I do not confine myself to the form or 10- cality of the corrugationsabove named for effecting the jogging motion of the vessel A, as thisform ma Y be varied, and the jogging de vice may be added to the lowerend of the shaft D, or other portions of the structure. Again, thisjogging of the vessel may be employed or not, as under somecircumstances it may be dispensed with, in which case the free end ofthe lever I is raised by means of the hand-wheel or nut, and the vesselA freed from contact with the ledge, or by means of the wheel the degreeor extent of joggin g motion is adjusted.

Heretofore the action of these screens has been slow or sluggish, and inaddition to this a serious evil results from the tendency of the pulp,after passing the interstices of the screen, to assemble into strings,so called, which adhere to the lower edges of the said interstices untilthey assume considerable size and length, and then drop into thescreened pulp below and enter into the sheet of paper with injuriousresults.

To facilitate the passage of pulp through the slits or interstices ofthe screen by preventing clogging of the same, and to obviate collectionof strings, before alluded to, I employ jets of water, as beforepremised; and to carry out this portion of my invention in one manner inwhich it may be effectually and economically accomplished, I proceed, inthe present instance, as follows: I place below the screen D, and withinthe walls of the cylinder A, a suitable reservoir, H, to contain water,which is supplied to it under suitable pressure, and constitutes afeeder to a series of upright jet-pipes, I I, &c., erected upon suchreservoir and communicating with its interior, the upper edge or mouthof each pipe I being in close proximity to the under side of the screen,in order not to be obstructed by passing through the body of pulp below.

The form, extent, and disposition of the discharge-orifices of the pipesI, will be a matter of practice, to which I do not restrict myself; butin my own use I arrange them as shown in the drawings-that is, long andattenuated, disposed radially of the cylinder, and so as to con'unaudits entire surface when revolving.

Thejets of water issuing from the pipes I impinge against the under sideof the screen D, and, to a great or less degree, force their way upwardthrough the interstices a, and thereby prevent obstruction of the latterand the formation and accumulation of the strings before alluded to, Thewater thus injected also serves to dilute the pulp, and provides thenecessary vehicle whereby the pulp is flowed upon the wire-cloth of themachine, through which such water finally escapes; and, if deemedadvisable, this water, after being expressed from the film. of pulp, maybe returned to the reservoir 11 and used over continuously, thuseffecting an economy in the use of water.

In practical operation of my device the vessel A is put in rotation at amoderate speed and pulp supplied to its interior from above the screen,the inlet-pipe being so arranged as preferably to deliver the pulp atthe center of the vessel. The centrifugal force generated by therevolution of the vessel A induces a current of the pulp, which setsoutward toward the circumference of the vessel, and thereby gives ampleopportunity for such pulp to be drawn downward through the intersticesof the screen D by the suction below, while at the same time the jets ofwater from below the screen are executing the functions required ofthem, as before explained.

I obtain in my device the effects of the jogging motion of screensheretofore in use; but as my jogging mechanism is placed preferably atthe bottom of the chest E, and immersed in the pulp therein, I dcaden toa great extent the noise incident to the present device.

I also obtain, by my system, in addition to the jogging motion ofordinary screens, the benefit of the jets of water, before explained,and the current of the pulp setting outward and distributing itselfuniformly over the surface of the screen, by the centrifugal force ofthe revolving vessel.

I am enabled to screen pulp much more rapidly than heretofore, and toprevent formation of strings, thus producing more perfect paper.

The ease with which the screenings, so called, may be removed from myscreen will commend my invention to paper-machine tenders, as it is onlynecessary to place the scoop in contact with the revolving surface ofthe screen, when its revolutions fill the scoop without effort on thepart of the tender.

My system of water-jets is applicable, with very advantageous results,to screens now in use, and maybe applied to them at small cost.

Having thus described the nature and purposes of my invention, I claim,and desire to secure by Letters Patent of the United States, thefollowing:

1. The combination, with a pulp-screen of paper-makin g machinery, ofmeans for directing a jet or jets of water upon the under side of suchscreen.

2. A pulp-screen for paper-makin g machinery composed of acylinder orvessel having a perforated or reticulated partition through which thepulp passes and is screened, the vessel being contained in a suitablecistern and being rotated by proper means. a

3. In combination with the rotary vessel and its screen, a device foreflecting jogging motions of such vessel and screen.

4. The combination, with the rotary vessel snvrnon L. GOULD.

Witnesses:

F. E. HITOHINGS, E. D. GOULD.

